The invention relates to a switch with at least one set of interacting contacts which is accommodated in the switch housing and can be seen through a transparent window, which contacts are arranged on the free ends of current-carrying strips which run towards the window.
A switch of this nature is generally known and has the drawback that after a period of time the window is no longer sufficiently transparent, owing to contamination, with the result that the position of the contacts can no longer clearly be seen. The reason for this is that when the contacts are separated when they are carrying current, an arc is formed, producing substances which are deposited on the window.
In U.S. Pat. No. 5,061,833 a switch of above cited type is described, in which the current-carrying strips have a U-shaped section adjacent to its contact and the opening of said section faces away from the window.
The object of the invention is to provide a switch of the type mentioned in the preamble which avoids the above drawback.
According to the invention, this object is achieved by the fact that a plate made from magnetizable material is arranged between the limbs of the U-shaped section of at least one strip.
Using the U-shaped section or sections generates a magnetic field at the location of the contacts which is such that the arc is blown away from the window. This counteracts contamination of the window.
The abovementioned blowing is improved by the plate from magnetizable material and can be improved by using measures described herein.